The present invention relates to synchronizing playback of a movie film and sound recorded on a record medium separate from the film at the time of photographing.
In the years since moving picture cameras and projectors and sound recording apparatus have been technically and economically within the means of amateurs, various means have been proposed for achieving more or less exact synchronization of the sound and picture as they are played back and projected together. Since the camera, projector and recorder/playback unit are driven by separate motors, some of which may be DC and others AC operated, rather wide discrepancies between sound and picture can develop during the course of playback even though the two are synchronized at the outset.
Prior systems which provide good synchronization of separately recorded sound and film have generally required special equipment incorporating the synchronizing features. That is, rather than utilizing equipment which the amateur user may already own, a special camera, projector and/or recorder-playback units must be purchased. Systems using electronic timing controls such as pulse generators, counters and logic circuits will obviously be quite expensive and therefore, to some extent, defeat the purpose of providing economical equipment.
A principal object of the present invention is to provide a sound movie system utilizing existing camera, projector and sound recording and playback equipment with relatively simple, inexpensive modifications while achieving good synchronization of sound and picture.
A further object is to provide means for synchronizing the projection of a silent moving picture with playback of a tape recording made simultaneously with filming of the movie which is extremely simple and economical and includes means for making selective manual adjustments of synchronism during playback.
Other objects will in part be obvious and in part appear hereinafter.